Categories: C=O Bond Formation >
Synthesis of imides
Among the reported examples of new reactivity of the hypervalent iodine reagent DMP (Dess-Martin periodinane) are the one-step oxidation of secondary amides to imides and N-acyl vinylogous carbamates or ureas and the direct oxidation of benzylic and related primary amines to the corresponding nitriles.
K. C. Nicolaou, C. J. N. Mathison, Angew. Chem. Int. Ed., 2005, 44, 5992-5997.
Visible-light-driven oxidations of various N-alkylamides proceed efficiently under mild conditions to provide imines by using Oxone as the oxidant in the presence of a catalytic amount of KBr in H2O/CH2Cl2 under irradiation by an 8 W white LED at room temperature. Experimental studies suggest that an imine, obtained from the substrate amide via a radical process, is the key intermediate.
C. Mei, Y. Hu, W. Lu, Synthesis, 2018, 50, 2999-3005.
A direct coupling of NH-amides with methylarenes under iodine/aqueous TBHP conditions enables a metal-free synthesis of imides. The optimized conditions worked also very well with benzaldehydes and benzyl alcohol and furnished the corresponding imides in good to excellent yields.
H. Aruri, U. Singh, S. Kumar, M. Kushwaha, A. P. Gupta, R. A. Vishwakarma, P. P. Singh, Org. Lett., 2016, 18, 3638-3641.
An iodine-catalyzed oxidative C-H/N-H cross-coupling enables an efficient construction of α-ketoimides in good to excellent yields from methyl ketones and benzamidines hydrochloride under metal-free and peroxide-free conditions.
X. Wu, Q. Gao, S. Liu, A. Wu, Org. Lett., 2014, 16, 2888-2891.
N-Acyl amino acids can be converted by oxidative decarboxylation induced by Ag+/Cu2+/S2O82- at room temperature in water into imides in good yields. Both N-benzoylvaline and N-benzoylleucine gave N-formylbenzamide, which possibly results from oxidative cleavage of an enamide intermediate.
W. Huang, M. Wang, H. Yue, Synthesis, 2008, 1342-1344.
The combination of hypervalent iodine(III) and TMSN3 promotes an oxidative cleavage of C-C double bonds of enamides under an air atmosphere. This method exhibits good functional group tolerance, broad substrate scope and mild conditions. The reaction also offers an approach to cyanobenzamides with synthetic potential for the preparation of industrial and pharmaceutical nitrogen- and oxygen-containing molecules.
G. Liu, Y. Li, J. Sheng, X.-S. Wang, Synthesis, 2017, 49, 3968-3974.